Technology review considers new cardiac ablation methods

Medical device manufacturers should focus on developing cardiac ablation systems that prolong the suppression of irregular heartbeats, according to a technology review.

Cambridge Design Partnership (CDP) undertook the work in response to a recent explosion in innovations in the atrial fibrillation market, now estimated to be worth around $15.7bn (£10bn) in the European Union.

The standard procedure involves making an incision in the neck or groin and threading a flexible catheter through to the heart where its special tip emits radio-frequency (RF) energy to essentially burn the cells that are propagating the irregular rhythm.

The technology is still relatively new, however, and there are few surgical support tools available, as CDP’s review co-author Keith Turner explained to The Engineer.

‘The heart wall has a thickness to it and you’re treating this on the inside surface, through to a certain depth, but you don’t really know how deep you’re going.

‘Because you’re basically burning the tissue, [surgeons] are scared about doing it too much and going right through. If you burn a hole and go through that’s really bad news, so they tend to underdo it; they don’t have any information on how deep they’ve gone and so they have to guess really.’

For the review, Turner and his team drew on a cross section of top industry and clinical figures, including leading electrophysiologists, as well as its own experience in designing medical products.

Some of the technologies considered included microelectromechanical system (MEMS) solutions for more precise positional delivery of the RF from the tip; advanced imaging technologies; force monitoring; thermal modelling; and plastic electronics.

‘What you will find is people who are developing all the new technologies are trying to address all sorts of problems: some are trying to make it faster, some are trying to make it easier, with less of a training requirement, and some are trying to make it easier to see what you’re doing,’ Turner said.

The outcome of the critical review, however, was that the most important goal for any new technology was to create ‘repeatable, contagious, lasting lesions’.

‘Trying to make it faster is fine — everyone wants faster, cheaper, easier — but what the doctors said to us was: “I’m not going to use a faster thing that doesn’t work first time round,”’ Turner added.

Feedback technologies that give an indication as to the maximum allowable extent of ablation before injury should, therefore, be a focus.

Turner said that technologies such as thermal modelling and impedance measures have not been that effective in trials; however, optical and force sensors have shown early promise.

CDP will now be working with medical device clients, mostly in the US, to advise them on technology acquisitions and strategies for developing and bringing existing portfolio technologies to market.